Application of Nickel-Titania Cermets to Zirconia Solid Oxide Fuel Cells

首先，建立了适用于固体氧化物燃料电池（SOFC）阳极的镍/钛金属陶瓷的制备工艺，特别是孔隙率控制，并测量了热膨胀率、机械强度、电导率和透气性。通过NiO与Ti的置换反应，得到了2NiO + Ti = 2Ni + TiO_2的陶瓷。随着退火温度的降低，金属陶瓷的显微组织逐渐细化。孔隙率随模压压力和退火温度的升高而降低。机械强度仅与孔隙率有关。随着孔隙率的增大，强度增大，30%时强度达到100 MPa。孔隙率为36.8%时的电导率为1000 μ m^<-1>。SOFC的渗透率在10^<-2> ~ 10^<-3> cm^4g^<-1>s^<-1>，孔隙度为30 ~ 40%。用等离子喷涂ZrO_2 - 8mol % Y_2O_3 （YSZ）薄膜的样品，测试了用该方法制备的陶瓷的电极性能。电极电导率随温度和PH_2O/PH_2比的升高而升高，在H_2 - H_2O （30 C）混合物中，在1000 C时达到150 Scm^<-2>。在1000℃的温度下，陶瓷不与YSZ薄膜发生反应。因此，该证书适用于SOFC。

In the first place, preparation technology for nickel/titania cermets suitable for anode in solid oxide fuel cells (SOFC), especially porosity control, has been established, and thermal expansivity, mechanical strength, electrical conductivity and gas permeability has been measured. Cermets were obtained by the displacement reaction between NiO and Ti powders, 2NiO + Ti = 2Ni + TiO_2. Microstructure of the cermets became finer with decreasing the annealing temperature. Porosity decreased with increasing the applied pressure in dieforming and the annealing temperature. Mechanical strength was related only to porosity. The strength became higher with increasing the porosity and was 100 MPa at 30 %. The electrical conductivity at a porosity of 36.8 % was 1000 Scm^<-1>. The gas permeability was sufficiently high for SOFC and was in the range 10^<-2> to 10^<-3> cm^4g^<-1>s^<-1> at a porosity of 30 to 40 %.Electrode performance of cermets obtained by the established method has been tested using the samples on which films of ZrO_2 - 8 mol % Y_2O_3 (YSZ) were plasma-sprayd. Electrode conductivity increased with increasing the temperature and the PH_2O/PH_2 ratio, and reached 150 Scm^<-2> at 1000ﾟC in a H_2 - H_2O (30ﾟC) mixture. Cermets did not react with YSZ films at 1000ﾟC.Therefore, this cermet was applicable to SOFC.